JP7828224B2 - Grinding wheel manufacturing method and grinding wheel - Google Patents

Description

The present invention relates to a method for manufacturing a grinding wheel used when grinding a workpiece, and to a grinding wheel.

Electronic devices such as mobile phones and personal computers are equipped with device chips containing devices such as ICs (Integrated Circuits). When manufacturing device chips, for example, the backside of a wafer on which multiple devices are formed on the front side is ground to thin it, and then the wafer is cut and divided into individual devices.

When grinding wafers, a grinding device is used. For example, a grinding device is known that performs rough grinding on the backside of a wafer using a rough grinding unit, and then performs finish grinding using a finish grinding unit (see Patent Document 1).

The rough grinding unit has a first spindle arranged approximately parallel to the vertical direction. A rough grinding wheel is attached to the lower end of the first spindle. Similarly, the finish grinding unit has a second spindle arranged approximately parallel to the vertical direction. A finish grinding wheel is attached to the lower end of the second spindle.

Grinding wheels, such as rough grinding wheels and finish grinding wheels, have an annular base made of metal. An annular groove of a predetermined width is formed on one side of the annular base along the circumferential direction of the annular base. Multiple grinding wheels (hereinafter referred to simply as grinding wheels) are arranged in this annular groove at approximately equal intervals along the circumferential direction of the annular base.

Each grinding wheel is fixed to the annular base with adhesive. However, the width of the annular groove is only a few millimeters, and more than half of each grinding wheel protrudes from one side of the annular base in the thickness direction of the blade. Therefore, if the grinding wheel is not fixed to the annular base with sufficient adhesive strength, the grinding wheel may fall off the annular base during grinding.

Japanese Patent Application Laid-Open No. 2000-288881

The present invention was made in consideration of these problems, and aims to improve the adhesive strength of the grinding wheel to the annular base.

According to one aspect of the present invention, there is provided a method for manufacturing a grinding wheel, comprising: an annular base formed of a metal material and having an annular groove formed circumferentially on one side thereof; an unevenness forming step for forming unevenness on one or both of the side and bottom surfaces of the annular groove by applying ultrasonic vibrations from an ultrasonic vibration imparting unit via water to the annular groove; and a grinding wheel fixing step for fixing a plurality of grinding wheels to the annular groove with an adhesive after the unevenness forming step.

According to another aspect of the present invention, there is provided a grinding wheel comprising: an annular base formed of a metal material and having an annular groove formed on one surface thereof along a circumferential direction; and a plurality of grinding stones fixed to the annular groove with an adhesive, wherein a first periodic asperity is formed on the side surface of the annular groove in a thickness direction perpendicular to the circumferential direction; a second periodic asperity is formed on the bottom surface of the annular groove in a radial direction perpendicular to the circumferential direction and the thickness direction; and a third asperity having a depth smaller than that of the first asperity and the second asperity is formed on one or both of the side surface and the bottom surface of the annular groove.

In one aspect of the present invention, a method for manufacturing a grinding wheel involves applying ultrasonic vibrations to the annular groove of the annular base via water from an ultrasonic vibration applying unit, thereby forming irregularities on one or both of the side and bottom surfaces of the annular groove (irregularity forming process). The irregularities formed in the annular groove by applying ultrasonic vibrations increase the contact area between the annular base and the adhesive, thereby improving the adhesive strength of the grinding wheel to the annular base.

In addition, a grinding wheel according to another aspect of the present invention has third asperities formed on one or both of the side and bottom surfaces of the annular groove, the third asperities having a depth smaller than the first and second asperities. The third asperities increase the contact area between the annular base and the adhesive, thereby improving the adhesive strength of the grinding wheel to the annular base.

FIG. 1 is a flow diagram of a method for manufacturing a grinding wheel. 10A and 10B are diagrams illustrating a step of forming irregularities. FIG. 3A is an enlarged cross-sectional view of the annular groove, and FIG. 3B is an enlarged view of region A in FIG. 3A. FIG. FIG. 2 is a perspective view of a grinding wheel. FIG. 1 is a schematic diagram of a universal testing machine. 10 is a graph showing test results of a bending test of a cantilever grinding wheel. FIG. FIG. 9(A) is an enlarged photograph of an area B to which ultrasonic vibration is not applied, and FIG. 9(B) is a schematic diagram of the cross-sectional outline of the disk-shaped base. FIG. 10(A) is an enlarged photograph of region B after cutting and sandblasting, and FIG. 10(B) is a schematic diagram of the cross-sectional outline of the disk-shaped base. FIG. 11(A) is an enlarged photograph of region B after cutting and application of ultrasonic vibration, and FIG. 11(B) is a schematic diagram of the cross-sectional outline of the disk-shaped base.

An embodiment of one aspect of the present invention will be described with reference to the accompanying drawings. Figure 1 is a flow diagram of a method for manufacturing a grinding wheel 2 (see Figure 5). First, with reference to Figures 4 and 5, the structure of the grinding wheel 2, in which multiple grinding wheels 6 are fixed to an annular base 4, will be described.

The grinding wheel 2 has an annular base 4 made of a metal material such as an aluminum alloy. The annular base 4 has an annular surface 4a and an annular surface 4b arranged generally parallel to each other. A grinding stone 6 (described below) is fixed to the surface 4a of the annular base 4 (the upper surface in Figure 5).

In contrast, the other surface 4b (the lower-upper surface in Figure 5) is fixed to a wheel mount (not shown) with bolts or the like. The outer diameters of the one surface 4a and the other surface 4b are approximately the same, and the outer peripheral side surface of the annular base 4 is a cylindrical side surface that is approximately perpendicular to the one surface 4a and the other surface 4b.

In contrast, the inner diameter of one surface 4a is larger than the inner diameter of the other surface 4b. Therefore, an inclined surface is formed on part of the inner peripheral side surface of the annular base 4. Furthermore, an opening 4c is formed in the center of the annular base 4 in the radial direction 4B, penetrating from one surface 4a to the other surface 4b.

An annular groove 4d is formed on one surface 4a, extending along the circumferential direction 4A of the annular base 4. The width of the annular groove 4d is a predetermined value, for example, between 2.0 mm and 4.0 mm. Multiple grinding wheels 6 are arranged at approximately equal intervals in the annular groove 4d.

Each grinding wheel 6 is formed by mixing a binder such as metal, ceramic, or resin with superabrasive grains such as diamond or cBN (cubic boron nitride), and then molding and firing the mixture. Each grinding wheel 6 has a width 6a (i.e., segment width) that is approximately the same as the width of the annular groove 4d.

The base end 6b of each grinding wheel 6 (see Figure 4) is fixed to the annular groove 4d with adhesive 7. In this embodiment, the adhesive 7 is a thermosetting resin such as epoxy resin, but the adhesive 7 is not limited to this example.

At least two-thirds of the height 6c of the fixed grinding wheel 6 protrudes above the surface 4a. The length of the portion of the height 6c of the grinding wheel 6 that protrudes above the surface 4a is called the segment height. The segment height is a predetermined value, for example, between 4.0 mm and 15.0 mm.

Multiple grinding fluid supply ports 8 are formed inward from the annular groove 4d on one surface 4a in the radial direction 4B of the annular base 4. Each grinding fluid supply port 8 is arranged at approximately equal intervals along the circumferential direction 4A of the annular base 4. During grinding, grinding fluid (not shown), such as pure water, is supplied to the grinding wheel 6 from each grinding fluid supply port 8.

Next, a method for manufacturing the grinding wheel 2 will be described with reference to the flow chart shown in Fig. 1. In the method for manufacturing the grinding wheel 2 according to this embodiment, first, as shown in Fig. 2, ultrasonic vibrations are applied to the annular groove 4d through water 10, such as pure water, to form irregularities in the annular groove 4d (irregularity forming step S10). Note that, hereinafter, the irregularities formed in the annular groove 4d by applying ultrasonic vibrations in the irregularity forming step S10 will be referred to as third irregularities _4e3 (see Fig. 3(B)).

Figure 2 shows the unevenness formation process S10. In the unevenness formation process S10, the annular base 4 is first immersed in a water tank 12 containing a predetermined amount of water 10, with one surface 4a facing upward. Then, with the lower end 16a of the vibration amplification transmission part 16 of the ultrasonic vibration imparting unit 14 positioned within the annular groove 4d, ultrasonic vibrations are imparted from the vibration amplification transmission part 16.

In this embodiment, the ultrasonic vibration imparting unit 14 has a bolt-clamped Langevin-type transducer (BLT) that includes a piezoelectric element. A conical horn (vibration amplifier) is connected to the BLT to amplify the ultrasonic vibrations.

In addition, a cylindrical vibration transmission rod (vibration transmission unit) is connected to the tip of the horn to transmit the ultrasonic vibrations amplified by the horn, and the horn and vibration transmission rod form the vibration amplification transmission unit 16. However, the configuration of the ultrasonic vibration imparting unit 14 is not limited to this example.

An oscillator (not shown) that generates a high-frequency electrical signal is electrically connected to the ultrasonic vibration imparting unit 14. The high-frequency electrical signal supplied from the oscillator causes the ultrasonic vibration imparting unit 14 to generate ultrasonic vibrations.

In the unevenness formation process S10 of this embodiment, the frequency of the ultrasonic vibrations is set to a predetermined value of 16 kHz or more and 100 kHz or less (e.g., 20 kHz), and the output is set to a predetermined value of 5.0 W or more and 100 W or less (e.g., 30 W).

Furthermore, ultrasonic vibrations are applied to the annular base 4 for at least one minute (more preferably at least three minutes) while the ultrasonic vibration imparting unit 14 is stationary, and then the ultrasonic vibration imparting unit 14 is translated a predetermined distance along the circumferential direction 4A of the annular groove 4d.

In this way, ultrasonic vibrations are applied to the entire annular groove 4d in the circumferential direction 4A by alternately repeating the application of ultrasonic vibrations and the translation of the ultrasonic vibration applying unit 14. As a result, third asperities _4e3 are formed on one or both of the side surface _4d1 (inner peripheral side surface _4d1A and outer peripheral side surface _4d1B ) and the bottom surface _4d2 of the annular groove 4d.

The water 10 does not contain abrasive grains or the like that may scratch the annular base 4. Therefore, it is presumed that the third irregularities _4e3 are formed by, for example, shock waves (i.e., cavitation effect) generated by the bursting of bubbles.

As shown in Figure 3(A), periodic irregularities formed when cutting the annular base 4 using a machining center remain on each of the side surfaces _4d1 (inner peripheral side surface _4d1A and outer peripheral side surface _4d1B ) and the bottom surface _4d2 .

More specifically, first irregularities _4e1 are formed periodically on the inner peripheral side surface _4d1A and the outer peripheral side surface _4d1B along the thickness direction 4C of the annular base 4. The first irregularities _4e1 in this embodiment are a plurality of grooves that are approximately parallel to one another and extend along the circumferential direction 4A.

Similarly, second irregularities _4e2 are formed periodically on the bottom surface _4d2 along the radial direction 4B of the annular base 4. The second irregularities _4e2 in this embodiment are also a plurality of grooves that are approximately parallel to one another and extend along the circumferential direction 4A. Fig. 3(A) is an enlarged cross-sectional view of the annular groove 4d.

3A, the circumferential direction 4A, the radial direction 4B, and the thickness direction 4C of the annular base 4 are perpendicular to one another. For ease of explanation, the first irregularities _4e1 on the side surface _4d1 and the second irregularities 4e2 on the bottom surface _4d2 are exaggerated in FIG. _3A . However, in reality, the first irregularities _4e1 and the second irregularities _4e2 are very small.

For example, the first and second irregularities _4e1 and _4e2 have a period (pitch) of 80 μm to 100 μm (e.g., 90 μm) and a depth of 20 μm to 100 μm (e.g., 30 μm). Therefore, the first and second irregularities _4e1 and _4e2 are generally almost invisible to the naked eye.

Fig. 3(B) is an enlarged view of region A on the bottom surface _4d2 in Fig. 3(A). Fig. 3(B) also shows the pitch 4f and depth 4g of the second asperities _4e2 formed on the bottom surface _4d2 . The pitch 4f is, for example, the distance between the tops of two adjacent mountains, but may also be the distance between the bottoms of two adjacent valleys.

In addition, in this embodiment, depth 4g is the distance between the highest peak and the lowest valley within a given length (i.e., the reference length) extracted from the roughness curve, and is also referred to as maximum height Rz (JIS B 0601:2013, ISO 4287:1997) and corresponds to maximum height Ry (JIS B 0601:1994).

By applying ultrasonic vibration to this annular groove 4d in the unevenness forming step S10, third unevenness _4e3 is formed on one or both of the side surface _4d1 and the bottom surface _4d2 , as shown in FIG. 3(B).

The third asperity _4e3 on the bottom surface _4d2 is composed of the surface of the periodic second asperity 4e2 and a plurality of holes formed on the bottom surface _4d2 in the asperity forming step S10. Similarly, the _third asperity _{4e3 on the side surface 4d1 is} composed of the surface of the periodic first asperity _4e1 and a plurality of holes formed on the side surface _4d1 in the asperity forming step S10.

The third asperity _4e3 has a depth 4h (e.g., 10 μm) that is smaller than the depth 4g of the first asperity _4e1 and the second asperity _4e2 . For example, as shown in FIG. 3B, the depth _4h of the third asperity _4e3 formed on the surface of the periodic second asperity 4e2 is defined as the maximum depth of the holes in the normal direction to the surface of the second asperity _4e2 when no holes are formed.

The third asperity _4e3 is formed substantially randomly, unlike the periodic first asperity _4e1 and second asperity _4e2 . In this embodiment, the third asperity _4e3 is formed on both the side surface _4d1 and the bottom surface _4d2 , but may be formed only on the bottom surface _4d2 or only on the side surface _4d1 .

After the unevenness forming process S10, the annular base 4 is removed from the water tank 12 and allowed to dry. Liquid adhesive 7 is then supplied to the annular groove 4d, after which multiple grinding wheels 6 are inserted into the annular groove 4d (see Figure 4). The adhesive 7 is then allowed to solidify, thereby fixing each grinding wheel 6 to the annular groove 4d with the adhesive 7 (grinding wheel fixing process S20). Figure 4 shows the grinding wheel fixing process S20.

Note that adhesive 7 is not limited to thermosetting resin. Adhesive 7 may also be a two-part mixture type room temperature curing resin that begins to harden when the base agent and curing agent are mixed, or an ultraviolet curing resin that begins to harden when exposed to ultraviolet light.

Fig. 5 is a perspective view of the grinding wheel 2 manufactured according to the flow diagram shown in Fig. 2. In this embodiment, the third irregularities _4e3 formed in the annular groove 4d by applying ultrasonic vibrations increase the contact area between the annular base 4 and the adhesive 7, thereby improving the adhesive strength (adhesion) of the grinding stone 6 to the annular base 4.

In the unevenness forming process S10, the annular base 4 can be placed on a rotatable table, and the table can be rotated relatively slowly at a predetermined rotation speed. Instead of rotating the table, a ring-shaped vibration transmission unit (not shown) that can fit into the annular groove 4d can be used as the vibration amplification transmission unit 16, and ultrasonic vibrations can be applied to the entire annular groove 4d simultaneously.

In the unevenness forming process S10, instead of immersing the annular base 4 in a water tank 12 containing water 10, ultrasonic vibrations may be applied to the annular groove 4d while water 10, such as pure water, is supplied from a nozzle (not shown) between the vibration amplification transmission unit 16 and the annular groove 4d.

Next, the experimental results of the bending test will be explained with reference to Figures 6 to 11. In this experiment, a universal testing machine (model number: AG50-kNG) 20 manufactured by Shimadzu Corporation was used. First, the configuration of the universal testing machine 20 will be explained with reference to Figure 6. Figure 6 is a schematic diagram of the universal testing machine 20.

The universal testing machine 20 has an indenter 22 that can be lowered along the Z-axis direction. The indenter 22 has a cylindrical shape with a diameter of 3 mm and is positioned so that the longitudinal direction of the cylinder is perpendicular to the Z-axis direction. In this experiment, the test piece 11 was fixed in place by a vice 24 attached to the bottom of the universal testing machine 20, and the indenter 22 was lowered at a rate of 1 mm/min.

The test piece 11 used in this experiment had a disk-shaped base 13 made of an aluminum alloy. One surface 13a of the disk-shaped base 13 was machined using a machining center, and periodic irregularities remained, similar to the side surface _4d1 and the bottom surface _4d2 of the annular base 4 described above (see Figures 9(A) and 9(B), etc.).

The pitch of the irregularities formed on one surface 13a of the disk-shaped base 13 is approximately 90 μm, and the depth (Rz) of the irregularities is approximately 30 μm. The surface 6d of the grinding wheel 6 corresponding to the base end 6b of the grinding wheel 6 inserted into the annular groove 4d was fixed to the surface 13a of the disk-shaped base 13 with adhesive 7.

In addition, we prepared a disk-shaped base 13 that had not undergone the above-mentioned unevenness formation process S10, and a disk-shaped base 13 to which ultrasonic vibrations had been applied using the unevenness formation process S10 in a predetermined area of the surface 13a to which the adhesive 7 was applied.

Specifically, two first test pieces 11 were created in which a grinding wheel 6 was fixed with adhesive 7 to a disk-shaped base 13 that had not undergone the above-mentioned unevenness formation process S10, and two second test pieces 11 in which the ultrasonic vibrations were applied for 30 seconds during the unevenness formation process S10.

Furthermore, two third test pieces 11 were created in which the ultrasonic vibrations were applied for one minute during the unevenness formation process S10, and two fourth test pieces 11 were created in which the ultrasonic vibrations were applied for three minutes during the unevenness formation process S10.

A one-component heat-curing epoxy resin was used as the adhesive 7. The adhesive 7 was applied at 160 g/ ^m2 to an area of the surface 13a corresponding to the surface 6d of the grinding wheel 6, and then solidified at 120°C for two hours. As a result, the grinding wheel 6 was fixed to the surface 13a in a cantilevered manner.

Then, with the disk-shaped base 13 fixed in place by the vice 24, the indenter 22 was lowered approximately perpendicular to the side of the grinding wheel 6. The maximum stress (MPa) applied to the indenter 22 was measured until the adhesive 7 broke and the grinding wheel 6 peeled off from the disk-shaped base 13.

Figure 7 is a graph showing the results of a bending test on a cantilever-shaped grinding wheel 6. Figure 7 shows the smaller (i.e., minimum) of the maximum stresses measured when the grinding wheel 6 peeled off from the disk-shaped base 13 for each of the first to fourth test pieces 11.

The minimum value of the maximum stress applied to the indenter 22 in the test on the two first test pieces 11 was 122.95 MPa. Furthermore, the minimum value of the maximum stress in the test on the two second test pieces 11 was 122.10 MPa.

Furthermore, the minimum maximum stress value in the test on the two third test pieces 11 was 127.35 MPa, and the minimum maximum stress value in the test on the two fourth test pieces 11 was 152.85 MPa.

As such, the longer the ultrasonic vibrations were applied, the better the adhesive strength (adhesion) of the adhesive 7 that bonds the disc-shaped base 13 and the grinding wheel 6. Based on the experimental results, it can be said that the time for applying ultrasonic vibrations to the area where the grinding wheel 6 is fixed is preferably 1 minute or more, and more preferably 3 minutes or more.

Next, we will explain the observation results of one surface 13a of the disk-shaped base 13 used in the above experiment. Figure 8 is a plan view of the disk-shaped base 13. Figures 9(A), 10(A), and 11(A) show enlarged photographs of region B, a portion of the area on one surface 13a where the grinding wheel 6 is fixed with adhesive 7.

Figure 9(A) is an enlarged photograph of region B on one surface 13a of the disk-shaped base 13 (corresponding to the first test piece 11) that has been machined using a machining center but has not been subjected to ultrasonic vibration. Figure 9(B) is a schematic diagram of a cross section of the outline of the disk-shaped base 13 in a plane parallel to the predetermined direction C in Figure 9(A) and perpendicular to the one surface 13a.

9B corresponds to the bottom of the periodic irregularities _13b1 formed on the surface 13a. These periodic irregularities _13b1 correspond to the first irregularities _4e1 and second irregularities _4e2 of the annular groove 4d.

Figure 10(A) is an enlarged photograph of region B on one surface 13a of the disk-shaped base 13 after cutting using a machining center and sandblasting. Figure 10(B) is a schematic diagram of the cross-sectional outline of the disk-shaped base 13 in a plane parallel to the predetermined direction C in Figure 10(A) and perpendicular to one surface 13a.

The dashed lines in Fig. 10(B) indicate that the periodic irregularities _13b1 formed on the surface 13a have disappeared. Also, as shown in Fig. 10(B), minute irregularities 13c are formed in a substantially random pattern on the surface 13a after sandblasting.

For the sandblasting process, a commercially available sandblasting device was used to process the disk-shaped base 13 at 0.5 MPa for 3 minutes using polygonal particles made of white alundum (WA) (i.e., fused alumina) material and having a median diameter (i.e., 50% diameter, median diameter) of 45 μm or more and 75 μm or less.

The above-described bending test was also performed on the sandblasted test pieces 11. The minimum maximum stress value in the test on the two sandblasted test pieces 11 was 136.85 MPa.

In this way, sandblasting can contribute to improving the adhesive strength of the adhesive 7 that bonds the disc-shaped base 13 and the grinding wheel 6. However, when sandblasting is performed, powder is sprayed onto the disc-shaped base 13 at high pressure, so the powder adheres to the disc-shaped base 13.

Therefore, when sandblasting the annular base 4, cleaning is required after processing to remove the powder from the annular base 4, which requires additional labor. The same problem occurs when sandblasting the annular base 4.

In contrast, when the irregularities are formed by applying ultrasonic vibrations, as in the irregularity formation process S10 described above, no abrasive grains are used, which has the advantage that cleaning after the irregularities are formed is not required.

Figure 11(A) is an enlarged photograph of region B after cutting using a machining center and application of ultrasonic vibration. Note that Figure 11(A) is a photograph of the disk-shaped base 13 (corresponding to the fourth test piece 11) to which ultrasonic vibration was applied for 3 minutes in the unevenness formation process S10.

Fig. 11(B) is a schematic diagram of the cross-sectional outline of the disk-shaped base 13 on a plane parallel to the predetermined direction C in Fig. 11(A) and perpendicular to the surface 13a. The dashed lines in Fig. 11(B) correspond to the valley bottoms of the periodic irregularities _13b1 formed on the surface 13a. As described above, the periodic irregularities _13b1 correspond to the first irregularities _4e1 and the second irregularities _4e2 .

As shown in Figure 11 (B), by applying ultrasonic vibrations, it is possible to form irregularities _13b2 (corresponding to the third irregularities _{4e3 )} that are finer than the periodic irregularities _13b1 on one surface 13a formed by cutting processing, while leaving the periodic irregularities 13b1.

The minute irregularities _13b2 formed by the application of ultrasonic vibrations increase the contact area between the disk-shaped base 13 and the adhesive 7, which is thought to improve the adhesive strength (adhesion) of the grinding wheel 6 to the disk-shaped base 13.

The technical scope of the present invention is not limited to the scope described in the above-described embodiments. The structures, methods, etc. described in the above-described embodiments can be modified as appropriate without departing from the scope of the present invention.

In one example, in the unevenness forming process S10 described above, the annular base 4 was immersed in water 10 in a water tank 12 so that one surface 4a of the annular base 4 faced upward, but as long as ultrasonic vibrations can be applied through the water 10, one surface 4a of the annular base 4 may face sideways or downward.

2: Grinding wheel, 4: Annular base, 4A: Circumferential direction, 4B: Radial direction, 4C: Thickness direction 4a: One side, 4b: Other side, 4c: Opening 4d: Annular groove, 4d ₁ : Side surface, 4d _1A : Inner peripheral side surface, 4d _1B : Outer peripheral side surface, 4d ₂ : Bottom surface 4e ₁ : First unevenness, 4e ₂ : Second unevenness, 4e ₃ : Third unevenness (unevenness)
4f: pitch, 4g: depth, 4h: depth 6: grinding stone, 6a: width, 6b: base end, 6c: height, 6d: one surface 7: adhesive 8: grinding fluid supply port 10: water, 12: water tank 11: test piece 13: disk-shaped base, 13a: one surface, 13b ₁ , 13b ₂ , 13c: unevenness 14: ultrasonic vibration imparting unit, 16: vibration amplification and transmission part, 16a: lower end 20: universal testing machine, 22: indenter, 24: vice A, B: area, C: predetermined direction S10: unevenness forming process, S20: grinding stone fixing process

Claims (2)

A method for manufacturing a grinding wheel, comprising:
an annular base formed of a metal material and having an annular groove formed along a circumferential direction on one surface thereof, and applying ultrasonic vibrations from an ultrasonic vibration imparting unit to the annular groove via water to form irregularities on one or both of a side surface and a bottom surface of the annular groove;
a grindstone fixing step of fixing a plurality of grindstones in the annular groove with an adhesive after the concave-convex forming step;
A method for manufacturing a grinding wheel, comprising: A grinding wheel comprising:
an annular base formed of a metal material and having an annular groove formed on one surface thereof along a circumferential direction;
a plurality of grinding wheels fixed in the annular groove with an adhesive;
Equipped with
a first concave-convex pattern is formed on a side surface of the annular groove in a thickness direction perpendicular to the circumferential direction,
a second concave-convex pattern is formed on a bottom surface of the annular groove in a radial direction perpendicular to the circumferential direction and the thickness direction,
A grinding wheel characterized in that a third asperity having a depth smaller than that of the first asperity and the second asperity is formed on one or both of the side surface and bottom surface of the annular groove.